Adding multiple git account

Generate ssh key

ssh-keygen -t rsa -b 4096 -C "<email address 1>"
// make sure to keep the file name different for different id
// eg: id_rsa_personal
//     id_rsa_work

Copy ssh key to respective GitHub/GitLab accounts

cat ~/.ssh/<id file name>.pub
//eg: cat ~/.ssh/id_rsa_personal.pub

Then copy the result and paste to Github -> Settings -> SSH key

Configure

vim ~/.ssh/config

Add the following

Host <host_name1>
    HostName github.com
    User git
    IdentifyFile ~/.ssh/<id file name 1>
Host <host_name2>
    HostName github.com
    User git
    IdentifyFile ~/.ssh/<id file name 2>

Example:

Host github.com
    HostName github.com
    User git
    IdentifyFile ~/.ssh/id_rsa_personal
Host [email protected]
    HostName github.com
    User git
    IdentifyFile ~/.ssh/id_rsa_work

Make gitconfig

vim ~/.gitconfig

Add the following:

[user]
    name = <default user>
    email = <default email>
[includeIf "gitdir:~/<the folder you will use for work>/"]
    path = ~/<the folder you will use for work>/.gitconfig

This basically tells git to use default user if not used grom work folder.

Create gitconfig

vim ~/<the folder you will use for work>/.gitconfig

Then add the following

[user]
    name = <work user>
    email = <work email>

Add ssh key

ssh-add id_rsa_personal
ssh-add id_rsa_work

Test

ssh -T github.com
ssh -T [email protected]

Now you should be able to make changes from respective accounts in work folder and other folders.